Interesting, I thought CDI was more common, maybe because I ride motorcycles. Which use CDI a lot.
Coil packs vary in design, but for the most part work the same way, however some will use a wasted spark system whereas others will only fire on the correct cylinder
Was watching a video about Harley Davidsons. They really are a pile of junk. The engineering is many places is, well, really, really poor. It's not even like they evolved and adapted with the times/tech, they don't/didn't. And.... are now dieing.
They used a single crank pin for 2 pistons, not because that was a good choice, but because they couldn't be bothered to have two crank pins, balance the engine and have a sane firing interval. They use a 45* firing interval as a result. So BANG, BANG................ BANG BANG. Then because they were cheap skates they decided that per-cylinger ignition was too much effort so they just fire both plugs. This results in the BANG, BANG, POP..... The POP is caused by the engine being so poorly made there is enough combustable exhaust gas in the exhaust strike to ignite!
With an unbalanced crank, the bike shakes violently when idleing. So they mounted the engine on rubber.... with a cheap and nasty steel frame that flexed. Resulting in many deaths caused by death wobble oscilations. They added a counter balance (to fix the unbalanced pistons) such that the vibration of the unbalanced mass was forward/back, not up/down, hence the shaking. The only saving grace is that when moving, some of that insane vibration is muted by the road motion.
I think the video making summed it up by saying, Harley's, you either get them or you don't. I don't.